Ultraviolet-absorbing polymers compositions and filter

ABSTRACT

THE INVENTION CLAIMS AN ULTRAVIOLET-ABSORBING FILTER LAYER COMPOSITION FORMED FROM AN AQUEOUS SOLUTION OF A HYDROPHILIC COLLOID HAVING DISPERSED THEREIN A HYDROPHOBIC COPOLYMER OBTAINED BY EMULSION POLYMERIZATION OF AT LEAST ONE A,B-ETHYLENICALLY UNSATURATED MONOMER AND OF AN ULTRAVIOLET-ABSORBING, SOLID, WATER-INSOLUBLE MONOMER OF THE FORMULA:   R-CH=C(-R&#39;&#39;)-CO-A-Z   WHEREIN Z IS H OR Z&#39;&#39;, WITH Z&#39;&#39; REPRESENTING A SUBSTITUTED BENZOTRIAZOLE GROUP OF THE FORMULA:   2-(2-HO,Y,Y&#39;&#39;-PHENYL),X,X&#39;&#39;-2H-BENZOTRIAZOLE   R IS H, -CH3, -CN, -COOH OR -COAZ&#39;&#39; R&#39;&#39; IS H, -CH3, OR -CH2COAZ&#39;&#39; A IS -O- OR -NH OR A AND R FORM TOGETHER A CYCLIC IMIDE GROUP, OR A AND R&#39;&#39; FORM TOGETHER A CYCLIC IMIDE GROUP, A BEING BOUND TO THE SUBSTITUTED THIAZOLE GROUP OF Z&#39;&#39; VIA THE CARBOCYCLIC PHENYL GROUP OR VIA THE CARBOCYCLIC BENZO GROUP. THE ULTRAVIOLET-ABSORBING FILTER LAYER COMPOSITION MAY BE USED FOR THE PROTECTION OF LIGHT-SENSITIVE PHOTOGRAPHIC MATERIALS AGAINST ULTRAVIOLET LIGHT AND FOR THE PRODUCTION OF ULTRAVIOLET FILTERS AND FILTER LAYERS.

United States Patent 3,813,255 ULTRAVIOLET-ABSORBING POLYMERSCOMPOSITIONS AND FILTER Marc Godfried Mannens, Mortsel, Jan Jaeken,Hove, Wilhelmus Janssens, Aarschot, and Jan Jozef Priem, Mortsel,Belgium, assignors to Agfa-Gevaert N.V., Mortsel, Belgium No Drawing.Original application May 17, 1971, Ser. No. 144,251, now Patent No.3,761,272. Divided and this application June 4, 1973, Ser. No. 366,594

Claims priority, application Great Britain, June 9, 1970,

27,977/70 Int. Cl. G03c 1/84 US. Cl. 117-333 6 Claims ABSTRACT OF THEDISCLOSURE The invention claims an ultraviolet-absorbing filter layercomposition formed from an aqueous solution of a hydrophilic colloidhaving dispersed therein a hydrophobic copolymer obtained by emulsionpolymerization of at least one a,5-ethylenically unsaturated monomer andof an ultraviolet-absorbing, solid, water-insoluble monomer of theformula:

wherein Z is H or Z, with Z representing a substituted benzotriazolegroup of the formula:

V X N on Y C I \N- x \N/ Y,

R' is H, --CH or -CH COAZ' or A and R form together a cyclic imidegroup,

or A and R form together a cyclic imide group,

A being bound to the substituted thiazole group of Z via the carbocyclicphenyl group or via the carbocyclic benzo group.

The ultraviolet-absorbing filter layer composition may be used for theprotection of light-sensitive photographic materials against ultravioletlight and for the production of ultraviolet filters and filter layers.

This is a division of application Ser. No. 144,251, filed May 17, 1971,now Pat. No. 3,761,272.

The present invention relates to ultraviolet-absorbing polymers, theiruse for the protection of light-sensitive photographic materials, theiruse for the production of ultraviolet filters and filter layers and, asindustrial product, the filters protecting and photographic materialsprotected from the injurious effects of ultraviolet radiation by the aidof these polymers.

Photographic light-sensitive elements can be protected from theinjurious effect of light by mixing ultravioletabsorbing compounds withthe light-sensitive compositions or by the provision of special filterlayers containing the ultraviolet-absorbing polymer. If the photographicelement is intended for use in color photography, the ultraviolet filterlayer need not be an outer layer, but may be an interlayer i.e. a layerprovided under the layer or layers that do not require the protectionand over the layer or layers that need protection. Ultravioletabsorbingpolymers may also be incorporated into the support (paper or film) orthe support may be provided with an ultraviolet-absorbing filter layerbefore the application of the light-sensitive emulsion layer or layers3,813,255 Patented May 28, 1974 thereto, in order to minimize thereflectance of light from the surface of the support.

We have found that primary dispersions of particular hydrophobiccopolymers, which are obtained by the emulsion copolymerization of thecorresponding monomers, can very easily be mixed with hydrophiliccolloid binder materials and form extremely useful utraviolet-absorbingfilter layers that are colorless, very stable to light, andphotographically inert.

According to the invention an ultraviolet-absorbing filter layercomposition is provided that is formed from a mixture of an aqueoussolution of a hydrophilic colloid binder material and a primarydispersion with a concentration of 5 to 60% by weight of a hydrophobicultraviolet-absorbing copolymer obtained by emulsion copolymerization ofat least one e fi ethylenically unsaturated monomer with acopolymerizable ultraviolet-absorb ing solid, water-insoluble monomeraccording to the following structural formula:

wherein:

Z=H or Z that represents a substituted benzotriazole group of theformula:

R' =H, CH or -CH COAZ (in the latter case R being H),

or A and R together with CH=CR'-CO- form a cyclic imide ring substitutedwith the benzotriazole group of Z (in this case R being H or CH;,),

or A and R together with -CCO form a cyclic imide ring substituted withthe benzotriazole group of Z (in this case R being H),

each of X, X, Y, and Y (same or dilferent) represents a hydrogen atom,an alkyl group of 1 to 4 carbon atoms, an alkoxy group, a halogen atom,a carboxy group, or a sulphonamido group,

or X and X together represent the atoms necessary to form a closedbenzene ring,

A being bound to the substituted benzotriazole group of Z via thecarbocyclic phenyl group or via the carbocyclic henzo group;

said ultraviolet-absorbing monomer constituting between about 2 and byweight of total monomer present, and said hydrophobic copolymer formingbetween 8 and 40% by weight of the total weight of dryultraviolet-absorbing filter layer.

The ultraviolet-absorbing monomers are derived from acrylic acid,methacrylic acid, ,B-cyano-acrylic acid, ,3- cyanomethacrylic acid,crotonic acid, maleic acid, fumaric acid, citraconic acid, mesaconicacid and itaconic acid and the corresponding half-esters andhalf-amides, or they are cyclic imides.

By primary dispersions latices are understood that have been, prepareddirectly by emulsion polymerization of monomers in aqueous medium,contrary to secondary latices, which are obtained by dispersingpreformed polymers in water, independently of the manner wherein thepolymers themselves have been prepared. These secondary latices can beprepared for instance by dissolving the polymers in an organic mediumthat is immiscible with water, dispersing the resulting solution inwater, and distilling the organic solvent whilst stirring.

(a) dispersing the water-insoluble, solid, ultravioletabsorbing monomerin water containing known emulsifying agents, together with a solventfor the monomer and possibly with at least one other cap-ethylenicallyunsaturated monomer, the solvent being taken from (i) organic solventsthat are inert in respect of the ultraviolet-absorbing monomer and thatdo not interfere with the free radical-addition polymerization thereof,

(ii) liquid, water-insoluble, ethylenically unsaturated monomers thatare copolymerizable with the ultraviolet-absorbing monomer, and

(iii) mixtures of (i) and (ii);

(b) adding to the liquid dispersion obtained by step (a) a knownpolymerization initiator,

(c) and agitating under free radical polymerization con ditions untilcopolymerization has occurred.

According to the above-mentioned process the comonomer(s) may be liquidcomonomer(s) and in some cases they may serve as solvent for thenormally solid monomer. The comonomer(s) may be selected to confer cer'tain required properties on the water-insoluble copolymer.

These and other data including examples of polymerization initiators,emulsifying agents, and suitable solvents as well as instructionsrelating to the formation of the initial emulsions and/or suspensionsare fully set out in the said United Kingdom Patent Specification andneed not be repeated here in detail.

Among the polymerization initiators that are suited for use in the aboveemulsion polymerization process may be mentioned: persulphates, e.g.ammonium and potassium persulphate, azonitrile compounds, e.g.4,4'-azobis (4-cyanovaleric acid) as well as peroxide compounds, e.g.benzoyl peroxide and hydrogen peroxide.

As described in the above United Kingdom Patent Specificationsurface-active compounds of various classes and that are known per soare available for use as emulsifying agents, i.e. soaps, sulphonates,and sulphates, cationic and amphoteric compounds and high-molecularweight protective colloids.

The latices obtained have a concentration of 5 to 60% by weight ofultra-violet-absorbing copolymer, whereas the copolymer itself comprisesbetween 2 and 70% by weight of polymerized ultraviolet-absorbingmonomer.

Ultraviolet-absorbing, solid, water-insoluble monomers suited foremulsion copolymerization with other ,[3-ethyl enically unsaturatedmonomers to form hydrophobic, ultraviolet-absorbing copolymers are e.g.:

2 (2-hydroxy-4-methacryloylaminophenyl) -2H- benzotriazole 2(2'-hydroxy-3 -methacryloylamino-5 '-methylphenyl) ZH-benzotriazole 22'-hydroxy-3 '-methacryloylamino-5 '-tert.butylphenyl)-2-H-benzotriazole 2 (2'-hydroxyphenyl) -5 -methacryloylamino-2H-benzotriazole 2 2'-hydroxy-4-methacryloyloxyphenyl -2H benzotriazole.

The ultraviolet-absorbing monomers of the invention are copolymerizedwith at least one other monomer containing at least one ethylenic group,such as acrylic acid, methacrylic acid, a-chloro-acrylic acid, theesters and amides derived from acrylic acid, a-chloro-acrylic acid andmethacrylic acid such as acrylamide, methacrylamide, ethyl acrylate,n-butyl acrylate, 2-ethylhexyl acrylate and lauryl methacrylate, vinylesters such as vinyl acetate, vinyl propionate and vinyl laurate,acrylonitrile, methacrylonitrile, aromatic vinyl compounds such asstyrene and its derivatives e.g. vinyl toluene, vinylacetophenone, andsulphostyrene, itaconic acid, citraconic acid, crotonic acid, vinylidenechloride, vinyl alkyl ethers such as vinyl ethyl ether, maleic acidesters, N-vinyl-2-pyrrolidone, N-vinylpyridine, 2- and 4-vinylpyridine.

The ethylenically unsaturated monomers suited for copolymermization withthe ultraviolet-absorbing monomers corresponding to the above generalformula'can be chosen so that such physical and/ or chemical propertiesof the resulting copolymer as its insolubility in water, itslcompatibility with the binder of a photographic colloid composition,into which it is to be incorporated, its flexibility, its thermalstability, etc. are favorably influenced. It is possible to introducee.g. plasticizing groups in the ultraviolet-absorbing copolymer by usinga comonomer carrying such groups, thus favorably influencing thebrittleness and flexibility of the layers, into which thecopolymer is tobe incorporated.

The invention is limited to the incorporation of theultraviolet-absorbing copolymers of the invention as primary dispersionsinto ultraviolet-absorbing filter layer compositions for the reasons setforth below. Indeed, these latices may contain high percentages ofcopolymer e.g. concentrations of up to 60% by weight and yet possess arelatively low viscosity. When said latices are incorporated intoemulsions, the viscosity of the latter is not influenced. With secondarydispersions of copolymers or with solutions of the copolymers in organicsolvents there can never be attained such high concentrations. Theviscosity of their mixtures with aqueous gelatin solutions increases sofast with rising concentrations that'coating becomes totally impossible.Moreover, by the use of the primary dispersions there can be dispensedwith the use of organic solvents or alkaline solutions as well as withspecial dispersing techniques for incorporating theultraviolet-absorbing copolymers.

We prefer to add the ultraviolet-absorbing copolymers of the inventionto the hydrophilic colloid 'binder mate rial in the form of a primarydispersion. Indeed, the particle size of secondary dispersions is oftenlarger and the stability of these dispersions is found to be inferior tothat of the primary dispersions. Besides, the concentration of theprimary dispersions can be much higher than could be obtained even withsecondary dispersions. Moreover, the secondary dispersions are not socompatible with hydrophilic colloids e.g. gelatin. When admixed, forinstance, with aqueous gelatin solutions they usually produce matlayers. The primary dispersions are usually quite compatible withaqueous gelatin solutions so that very clear layers can be obtainedindeed.

The hydrophilic colloid binder material may be gelatin, colloidalalbumin, zein, casein, a hydrophilic cellulose derivative e.g.hydroxyethyl cellulose, or a synthetic hydrophilic colloid such aspolyvinyl alcohol and poly-N- vinyl pyrrolidone. If desired compatiblemixtures of two or more of the hydrophilic colloids may be employed.

The primary dispersion of hydrophobic ultravioletabsorbing copolymer ismixed with an aqueous solution of a hydrophilic colloid binder materialin such a ratio that between about 8 and 40% by weight ofultravioletabsorbing copolymer calculated on the total weight of the dryultraviolet-absorbing filter layer is present. The concentration of theultraviolet-absorbing compositions is not critical. Usually 0.2 to 1 g.of ultraviolet-absorbing copolymer is used per square meter of filterlayer. The optimum coating concentrations depend on the particularultraviolet-absorbing copolymer used, on the particular photographicelement to be protected, and on the extent of protection desired. Theoptimum coating concentrations for a given photographic element can bedetermined by methods well known in the art.

The ultraviolet-absorbing copolymers of the invention are not only usedin filter layers or on photographic lightsensitive materials, but theycan also be used in optical 5 filters such as taking filters and filtersin different kinds of densitometers.

It was interesting to form primary latexes of ultravioletabsorbingcopolymers with benzotriazole nuclei and to add them to aqueoussolutions of colloid binder materials. 'Ultraviolet-absorbing compoundsshould indeed have a high fastness to light and thus be very resistantagainst the action of ultraviolet radiation. Ultravioletabsorbingcompounds should be resistant also against heat and humidity and theirspectral properties should be excellent. Their extinction coeificient isparticular should be as high as possible. Normally the knownultravioletabsorbing compounds have one or several of these propertiesto a greater or less degree. The copolymers of the invention withbenzotriazole nuclei possess all these properties in a very high degree,so that they are very suited for use as ultraviolet-absorbing compoundsin photographic filter layers and optical filters.

The ultraviolet-absorbing copolymers can be mixed in primary dispersionform with an aqueous solution of a colloidal binder, e.g. gelatin,cellulose esters, synthetic resins (such as polyvinyl acetals andhydrolyzed polyvinyl acetate), and the resulting mixture is coated onthe light-sensitive layer of the photographic element. When thephotographic element is intended for use in color photography, theultraviolet filter layer need not be an outer layer. The filter layermay indeed be applied to one of the layers subject to the harmfuleffects of ultraviolet radiation. The ultraviolet-absorbing layer mayalso be coated directly on the support, which may have been providedwith known subbing layer or layers before the application oflight-sensitive layers thereto. Finally, the mixture of primarydispersion of ultraviolet-absorbing copolymer and of an aqueous solutionof a hydrophilic colloid binder material may be incorporated into films,foils, or layers of plastic, or coated as a layer thereon, and theresulting products can be used as protective filter layers or films e.g.in optical filters and in filters used in densitometers, and asprotective layers upon layers containing substances susceptible todegradation or change under the action of ultraviolet radiation, e.g.photographic color prints.

Thefollowing preparations describe the manufacture of theultraviolet-absorbing monomers and their emulsion copolymerization withother ethylenically unsaturated monomers.

PREPARATION 1 2 (2-hydroxy-4-methacryloylphenyl -2H-b euzotriazole 55.2g. o-nitroaniline are dissolved warm in 80 ml. of acetic acid. 140 ml.of concentrated hydrochloric acid (35%) are added to the resultingsolution whilst stirring. The hydrochloride of o-nitroanilineprecipitates. The product is cooled to 20 C., whereupon 200 g. oficewater are added. The suspension is then diazotized at C. with 27.6 g.of sodium nitrite in 50 ml. of water. After filtration the resultingsolution is added dropwise at 0 to 5 C. to a solution of 65.5 g. ofm-aminophenol in 1.5 l. of water comprising 120 ml. of hydrochloric acid(35%). A red dye separates. After stirring for 5 hours the resulting6[(o-nitrophenyl)-azo]-m+aminophenolhydrochloride is filtered withsuction and dried.

The product is suspended in 750 ml. of water, which is then neutralizedwith 5 N sodium hydroxide. Subsequently, a solution of 96 g. of sodiumhydroxide in 480 ml. of water is added. 78.5 g. of zinc powder is thenadded portionwise in min. at room temperature whilst stirring. After 30min. 100 ml. of 5 N sodium hydroxide are added as well as 10 g. of zincpowder. The solution being decolorized now is filtered. The filtrate iscooled, whereupon 250 ml. of acetic acid are added thereto. Theresulting precipitate is filtered with suction, washed until free ofacid, and dried. It is then recrystallized from n-butylacetate.

The 2(2'-hydroxy-4'-aminophenoyl)-2H-benzotriazole formed melts at 206C.

6.78 g. of the latter product are dissolved at 50 C. in 60 ml. ofanhydrous dioxan. To the resulting solution 2.77 g. of anhydrous sodiumhydrogen carbonate and mg. of m-dinitrobenzene as inhibiting agent areadded. The reaction mixture is stirred at 50 C. whilst adding 3.12 ml.of methacryloyl chloride dropwise. The mixture is then stirred for 5hours at 50 C.

The reaction mixture is poured out on 200 ml. of icewater and theresulting precipitate is filtered with suction, collected and dried. Theprecipitate is boiled up with 25 ml. of methanol, filtered with suctionwhile still hot, and washed with hot methanol.

2(2' hydroxy 4' methacryloylamino-phenyl)-2H- benzotriazolecorresponding to the following structural formula is formed:

The resulting product melts at 208 C.

PREPARATION 2 2(2-hydroxyphenyl)-5-methacryloylamino-2H- benzotriazole Asolution of 27.2 g. o-aminophenol in 250 ml. of water and 83 ml. ofhydrochloric acid (35%) is diazotized at 0 C., with a solution of 17.2g. of sodium nitrite in 35 ml. of water and then added at once to acooled solution of 36.1 g. of m-phenylenediamine hydrochloride in 500ml. of water.

To this stirred and cooled solution a solution of 170 g. of sodiumacetate in 250 ml. of water is added dropwise, whereupon there isstirred for 2 hours more at 5 C. and for 2 hours at room temperature.The pH of the reaction mixtureis then adjusted to 8 by addition ofconcentrated ammonium hydroxide. The dye is filtered with suction andwashed with water.

Yield: 42 g. of 2(2,4'-diaminophenylazo)-phenol melting at 169 C.

45.6 g. of this product are dissolved in 300 ml. of ethylene glycolmonomethyl ether and added to a stirred solution of 150 g. ofcopper(II)sulphate-pentahydrate in 360 ml. of water and 600 ml. ofconcentrated ammonium hydroxide. After stirring for 2 hours at 95 C. andthen cooling, the product is filtered with suction and washed with waterto a colorless filtrate.

Subsequently the precipitate is stirred thoroughly for 1 hour in 500 m1.of 5 N hydrochloric acid, filtered with suction, and again suspended in200 ml. of water adjusted to pH 8 by addition of concentrated ammoniumhydroxide, again filtered with suction, Washed with water, and dried.After recrystallization from n-butyl acetate and simultaneous treatmentwith active: carbon, 43 g. of 2(2'- hydroxyphenyl) 5 aminoZH-benzotriazole melting at 213 C. are obtained.

11.3 g. of this product and 0.1 g. of hydroquinoneare dissolved at 70 C.in m1. of dioxan and then admixed with 6.3 g. of sodium hydrogencarbonate. To theresulting stirred solution a solution of 5.1 ml. ofmethacryloyl chloride in 10 ml. of dioxan is added in 30 min. at'60' C.The reaction mixture is then poured out in water, whereupon the productis filtered with suction, washed monomethyl ether.

7 Yield: 11.1 g. of2(2'-hydroxypheny1)-5-methacryloylamino-2H-benzotriazole according tothe following formula:

This product melts at 201 C.

PREPARATION 3 2(2-hydroxy-3'-methacry1oylamino-5'-methylphenyl)-2H-benzotriazole 25 ml. of nitric acid are added dropwise to a stirredsolution of 67.5 g. of 2(2'-hydroxy-5'-methylphenyl)-2H- benzotriazolein 700 ml. of acetic acid at 70 C. 15 min. after the addition of thetotal amount of nitric acid the reaction mixture is cooled, whereuponthe precipitate is filtered with suction and washed with acetic acid andmethanol.

Yield: 70 g. of 2(2'-hydroxy- -nitro--methylphenyl)- 2H-benzotriazolemelting at 181 C.

69.5 g. of this compound in 500 ml. of dioxan are reduced at 60 C. with5 ml. of Raney nickel and a hydrogen pressure of 1500 p.s.i. Afterfiltering 01f of the Raney nickel the solution is cooled. A crystallineprecipitate is filtered with suction and recrystallized fromdimethylformamide.

Yield: 27.5 g. of 2(2 hydroxy 3 amino-5'-methylphenyl)-2H benzotriazole.

Analogously to the last part of Preparation 12(2'-hydroxy-3-methacryloylamino-5-methylphenyl)-2H-benzotriazolemelting at 157 C. is formed therefrom. The

product is recrystallized from n-butyl acetate and corresponds to thefollowing structural formula:

PREPARATION 42(2'-hydroxy-3'-methacryloylamino-5-tert.butylphenyl)2H-benzotriazole 26ml. of nitric acid are added dropwise at 40 C. to a stirred solution of67 g. of 2(2-hydroxy- '-tert.butylphenyl)-2H-benzotriazole in 700 ml. ofacetic acid. The mixture is stirred for 1 hour at 40 C. and then pouredout in water. The precipitate is filtered with suction, washed withwater until free of acid, dried, and recrystallized thrice fromdimethylformamide.

Yield: 41 g. of2(2'-hydroxy-3'-nitro-5'-tert.butylphenyl)-2H-benzotriazole melting at207 C. 40.5 g. thereof in 500 ml. of dioxan are reduced at 60 C. with 3ml. of Raney nickel under a hydrogen pressure of 1500 p.s.i. Afterfiltration oif the Raney nickel the filtrate is poured out in water, theresidue is filtered with suction, washed with water, dried, andrecrystallized from acetonitrile. Yield: 24.8 g. of 2(2' -hydroxy3-amino-5'-tert.butylphenyl)-2H-benzotriazole melting at 179 C.

Analogously to the last part of preparation 1 2(2'-hydroxy 3methacryloylamino-5-tert.butylphenyl)-2H- benzotriazole melting atl70172 C. is formed therefrom. After recrystallization from ethylacetate the prodnet corresponding to the following structural formula isobtained:

PREPARATION 5 2 2-hydroxy-4'-methacryloyloxyphenyl) -2H- benzotriazoleTo a hot solution of 13.8 g. of o-nitroaniline 50 ml. of hydrochloricacid (35%) is added, so that the hydrochloride is formed. After theaddition of 50 g. of ice the suspension is diazotized at 0 C. with asolution of 6.9 g. of sodium nitrite in 15 ml. of water. Afterfiltration the diazonium solution is added dropwise at 0 to 5 C. to astirred solution of 13.2 g. of resorcinol in 250 ml. of water. Fourhours later the azo dye is filtered with suction, washed with water, anddried. Yield: 22.6 g. of 4 [(2' nitrophenyl) azo] resorcinol melting atapproximately 220 C. (decomposition).

22 g. thereof are added to a stirred solution of 20.4 g. of sodiumhydroxide in 200 ml. of water and 100 m1. of ethanol. The sodium salt of4-[(4nitr0phenyl)-azo]- resorcinol precipitates partially.

Whilst thoroughly stirring 16.8 g. of zinc powder are added at C. Thereaction mixture decolorizes within 15 min. After filtration of the zincpowder, the filtrate is acidified with 60 ml. of acetic acid and cooled.The precipitate is filtered with suction, washed with ethanol, anddried. Yield: 14.3 g. of 2(2,4' dihydroxyphenyl)-2H- benzotriazolemelting at 260 C.

6.1 g. thereof are suspended in 50 ml. of dioxan comprising 20 ml. ofacetonitrile and 2.33 ml. of pyridine. At room temperature 2.78 ml. ofmethacryloyl chloride are added dropwise. The reaction mixture is pouredout in Water; the precipitate is filtered with suction, washed withwater, dried and finally recrystallized twice from acetonitrile.

Yield: 0.5 g. of 2(2'-hydroxy 4' methacryloyloxyphenyl)-2H-benzotriazolemelting at 184 C. and corresponding to the following structural formula:

PREPARATION 6 Preparation of a primary dispersion of co[n-butylacrylate/2(2'-hydroxyphenyl) 5 methacryloylamino-ZH- benzotriazole] In areaction vessel are brought 250 ml. of demineralized water, 2.5 g. ofsodium salt of oleylmethyltauride, 20 g. of 2(2'-hydroxyphenyl) 5methacryloylamino-2H-benzotriazole (of Preparation 2) and 12.5 ml. oftetrahydrofuran. The suspension is rinsed for 10 min. with nitrogen andthen heated to C. At this temperature 7.5 g. of nbutylacrylate areadded. The mixture is then heated further to C. 2.5 ml. of a 5% aqueoussolution of the sodium salt of 4,4'-azo-bis(4-cyanovaleric acid) areadded. After 3 min. 22.5 g. n-butyl acrylate and 5 ml. of a same 5%aqueous solution of the sodium salt of 4,4'-azo-bis(4- cyanovalericacid) are added in 1 hour to two dropping funnels. There is then stirredfor 30 min. at -86 C., whereupon another 2.5 ml. of the 5% aqueoussolution are added. Finally the mixture is heated at 8586' C. for 50 mm.

The residual monomer and tetrahydrofuran are evaporated in a slightvacuum, whereupon the latex is cooled. 720 mg. of the sodium salt ofoleylmethyltauride are then added per 100 ml. of latex aspost-stabilizer.

The latex volume is 280 ml. The concentration of the copolymer in thelatex is 17.1% by weight. The copolymer is composed of recurring unitsaccording to the following structural formulae:

A nitrogen analysis of the separated copolymer proved that it contained35.2% by weight of units of the ultraviolet-absorbing monomer.

PREPARATION 7 Preparation of a primary dispersion of co[n-butylacrylate/ 2(2'-hydroxy-3'-methacryloylamino-5 methylphenyl)-2H-benzotriazole] In a reaction vessel are placed 180 ml. ofdemineralized water, 16 g. of 2( 2-hyroxy 3' methacryloylamino-5'-methylphenyl)-2H-benzotriazole (see Preparation 3), and 2 g. of thesodium salt of oleylmethyltauride. The resulting suspension is stirredfor 30 min. at room temperature whilst rinsing with nitrogen.

The mixture is heated to 90 C. and then admixed with 7 g. of n-butylacrylate. After emulsification for 5 min., 0.8 ml. of a 5% aqueoussolution of the sodium salt of 4,4-azo-bis(4-cyanovaleric acid) areadded. The polymerization starts after a stirring period of 3 min. In 25min. 17 g. of nbutyl acrylate and 2.4 ml. of a same 5% aqueous solutionof the sodium salt of 4,4'-azo-bis(4- c3 anovaleric acid) are added. Themixture is then stirred for 40 min. at 95 C. and subsequently another0.8 ml. of the 5% aqueous solution are added. The mixture is thenallowed to polymerize further for 1 hour at 95 C. Traces of residualn-butyl acrylate are removed by evaporation in slight vacuum, whereuponthe yellow latex is cooled and filtered. As post-stabilizer an amount of850 mg. of the sodium salt of oleylmethyltauride per 100 ml. of latex isthen added.

The latex has a copolymer concentration of 21.3% and the copolymerconsists of recurring units according to the following structuralformulae:

and

10 PREPARATION 8 Preparation of a primary dispersion of co[n-'butylacrylate/ 2(2'-hydroxy 3' methacryloylamino 5'tert.butylphenyl)-2H-benzotriazole] In a reaction vessel are placed 150m1. of demineralized water, 14 g. of 2(2-hydroxy-3l'-methacryloylamino5'- tert.butylphenyl)-2H-benzotriazole (see Preparation 4), and 1.75 'g.of the sodium salt of oleylmethyltauride. The suspension is stirred for30 min. at room temperature and then heated to 75 C. An amount of 21 g.of n-butylacrylate is added, whereupon the mixture is heated further to-92 C. In 5 min. 25 ml. of a 5% aqueous solution of the sodium salt of4,4'-azo-bis(4-cyanovaleric acid) are added dropwise. The temperaturerises to C. There is stirred then for 3 0 min. at 95 C., whereupon 1 ml.of a same 5% aqueous solution of the sodium salt of4,4'-azobis(4-cyanovaleric acid) is added. After 1 hr. of stirring at 95C. the latex is freed from residual butyl acrylate in a slight vacuum,then cooled, and filtered.

Subsequently 270 mg. of the sodium salt of oleylmethyltauride are addedas post-stabilizer per ml. of latex.

The latex contains 17.6% by weight of copolymer that is composed ofrecurring units corresponding to the following structural formulae:

and

and

A nitrogen analysis of the collected copolymer proved that it contained27.2% by weight of units of the ultraviolet-absorbing monomer.

PREPARATION 9 In Preparation 6 a method has been described for thepreparation of small quantities of a primary dispersion of co[n-butylacrylate/2(2-hydroxyphenyl)-5-methacryloylamini-2H-benzotriazole]According to the following preparation large quantities of the sameprimary dispersion can be obtained.

In a reaction vessel of 20 l. were brought 13.3 1. demineralizecl water,360 g. of sodium salt of oleylmethyltauride and 1440 g. of2(2'-hydroxyphenyl)-5-methacryloylamino-ZH-benzotriazole (of Preparation2). The whole was stirred slowly for 30 min., while rinsing the spaceabove the liquid reaction mixture with a stream of nitrogen. Thereafterthe suspension was heated to 82 C. and rinsing with nitrogen wasterminated. At 80-83 C. one fourth (540 g.) of the total amount ofn-butyl acrylate (2160 g.) was added, whereafter the mixture was furtherheated until 90-93 C. At this temperature 180 ml. of a 5% aqueoussolution of the sodium salt of 4,4- azo-bis(4-cyanovaleric acid) wereadded. Polymerization started after a few minutes and in 2 hours 1640 g.of nbutyl acrylate and 540 ml. of the 5% aqueous solution of the sodiumsalt of 4,4-azo-bis(4-cyanovaleric acid) were simultaneously anddropwise added. Polymerization proceeded further for 90 min. at 95-97 C.

The primary dispersion obtained was freed from residual monomer bydistilling off approximately 2 l. of liquid where-after the latex wascooled and filtrated. As post-stabilizer were added 0.65 g. of thesodium salt of oleylmethyltauride.

The latex volume was 17 l. and had a concentration of 20.65% by weight.The copolymer particles had an average diameter of 400 A.

The primary dispersion of copolymer thus formed was completely misciblewith gelatin and the copolymer had an absorption maximum at 350 nm.

The copolymer was composed of the same recurring units as described inPreparation 6. A nitrogen analysis of the separated copolymer provedthat it contained 34.6% by weight of the ultraviolet-absorbing monomer.

Example 1 11.7 ml. of phenol as hardening agent, 4.25 ml. of butyl esterof sulphonated castor oil as wetting agent, and 3.75 ml. of latex of theultraviolet-absorbing copolymer co[n-butyl acrylate/2(2' hydroxyphenyl)5- methacryloylamino-ZH-benzotriazole] of preparation 6 were added to117 g. of gelatin and water was added to a volume of 1000 ml. Thisamount was coated on a glass plate having a surface of 1 m2 and thelayer was dried. In this manner an ultraviolet-absorbing filter wasobtained, which could be used as taking filter in photography and as afilter in a densitometer. The filter had an absolute maximum absorptionat 352 m and a molar extinction coefficient of 1.72 This filter was veryresistant against ultraviolet radiation.

In this example the latex of the ultraviolet-absorbing copolymer couldbe replaced by a same amount of latex obtained according to Preparations7 and 8, i.e. in the first case the latex of the ultraviolet-absorbingco[n-butyl acrylate/2(2'-hydroxy-3'-methacryloylamino 5'methylphenyl)-2H-benzotriazole] and in the second case the latex ofco[n-butylacrylate/2(2'-hydroxy-3methacryloylamino-5'-tert.butylphenyl)-2H-benzotriazole],which had a maximum absorption at 316 and 315 m respectively.

Example 2 A photographic multilayer material as used for the preparationof direct-positive color images was formed. Each of three integrallycoated emulsion layers was sensitized to one of the primary colors,namely blue, green, and red. The top layer was sensitive to blue lightand contained a color coupler for the yellow image. The middle layer wassensitive to green light and contained a color coupler for the magentaimage, whereas the bottom layer was sensitive to red light and containeda color coupler for the cyan image. A yellow filter layer separated theblue-sensitive and the green-sensitive layers. The different colorcouplers and oxidizing coupling compounds were those described inExample 10 of the United Kingdom Patent Specification 990,628.

65.4 ml. of latex of co[n-butylacrylate/2(2-hydroxyphenyl)-5-methacryloylamino 2H benzotriazole] (seePreparation '6) were added to 400 ml. of distilled water, wherein 25 g.of gelatin had been dissolved and subsequently the mixture was dilutedwith distilled water to a volume of 500 ml. and the pH of the mixturewas adjusted to 7 by addition of sodium hydroxide. Finally, 5 ml. ofsaponine and 2 ml. of a 1.25% aqueous solution of chrome alum wereadded.

On the resulting multilayer color reversal photographic material therewas then coated an ultraviolet-absorbing layer from the thus formedcoating composition at a ratio of 50 g./m. and the layer was then dried.After treatment in the known photographic baths for color reversalphotographic materials the film was subjected to resistance tests. Thesetests consisted in exposing the material for 30 h. to the radiation of a2000 watt. xenon lamp and in exposing it for 48 hrs. at 60 C. to arelative humidity of 95%. In both cases the film protected by theultraviolet-absorbing layer did not show any signs of yellowing orfading, whereas in an analogous multilayer color reversal photographicmaterial that did not comprise an ultraviolet-absorbing layer,considerable changes took place in the color rendering.

Example 3 The ultraviolet-absorbing layer of Example 2 was coated on aconventional color reversal photographic film to serve as a takingfilter. The resulting color reversal transparency was completely freefrom blue shadowing and blue fringing.

In the same way a conventional color negative film was coated with alatex of an ultraviolet-absorbing copolymer according to Preparation 6mixed with an aqueous solution of gelatin. The ultraviolet-absorbinglayer completely eliminated blue shadowing and blue fringing in theresulting processed color negative.

Example 4 To a 2.5% aqueous solution of gelatin 16 g. of a latexaccording to Preparation 6, comprising 20% by weight of solids, wereadded per gram of gelatinas well as the usual coating aids (wettingagents and hardening agents). The resulting mixture was coated at aratio of 1 g. of gelatin per m2 to form a covering layer on aconventional photographic silver halide multilayer color material. Thiscovering layer was intended to protect the colors obtained after theprocessing against the influence of ultraviolet radiation. The colorstability of the finished image was improved considerably thereby.

Example 5 The back of a multilayer color reversal photographic materialwas coated at a ratio of 1.5 g. of gelatin per m2 with a solution ofgelatin and an antihalation dye, to which 10 g. of the latex of theultraviolet-absorbing copolymer of Preparation 6 had been added per gramof gelatin. The resulting antihalation layer served to protect adiapositive color material from light striking the back of the material,as occurs during projection or in diapositive show-glasses. Theantihalation dye could be a known organic dye or common colloidal blacksilver. The results obtained with this ultraviolet-absorbing backinglayer were very good.

Example 6 A paper sheet coated with a baryta layer was covered with agelatin layer containing per gram of gelatin 15 g. of latex of theultraviolet-absorbing copolymer prepared according to Preparation 6. Theresulting ultraviolet-absorbing layer was coated with a series oflight-sensitive photographic layers and other layers to produce amulticolor photographic material. The consecutive layers were thefollowing:

(1) a blue-sensitive gelatin silver chlorobromide emulsion containing acoupler for the yellow image,

(2) a gelatin interlayer,

(3) a green-sensitive gelatin silver chlorobromide emulsion containing acolor coupler for the magenta image,

(4) a gelatin interlayer,

(5) a red-sensitive gelatin silver chlorobromide emulsion containing acolor coupler for the cyan image,

(6) a gelatin protection overcoat.

The resulting sensitive multicolor photographic material could beexposed and processed to produce the desired dye image. The material wasvery fast yellowing.

The same latex of Preparation 6 could also be applied alone or inadmixture with an aqueous solution of gelatin to a color print or paperby spraying or brushing to form a protective layer against ultravioletradiation.

We claim:

1. An ultraviolet-absorbing filter layer composition, characterized inthat the filter layer is formed from a mixture of an aqueous solution ofa hydrophilic colloid binder material and a primary dispersion with aconcentration of 5 to 60% by weight of a hydrophobicultraviolet-absorbmg copolymer obtained by emulsion copolymerization ofat least one a,fi-ethylenically unsaturated monomer with acopolymerizable ultraviolet-absorbing, solid, Water-insoluble monomeraccording to the following structural formula:

:H=(|:-o- Az R R wherein: Z=H or Z that represents a substitutedbenzotriazole group of the formula:

X OH

Y Q X! R'=H, -CH or -CH COAZ' (in the latter case R being H),

or A and R together with CH=CR'-CO- form a cyclic imide ring substitutedwith the benzotriazole group of Z (in this case R being H or CH or A andR together with -CCO-- form a cyclic imide ring substituted with thebenzotriazole group of Z (in this case R being H), at least one of R, Ror Z must include the substituted benzotriazole group of Z,

each of X, X, Y and Y (same or different) represents a hydrogen atom, analkyl group of 1 to 4 carbon atoms, an alkoxy group, a halogen atom, acarboxy group, or a sulphonamido group,

or X and X together represent the atoms necessary to form a closedbenzene ring,

A being bound to the substituted benzotriazole group of Z via thecarbocyclic phenyl group or via the carbocyclic benzo group;

said ultraviolet-absorbing monomer constituting between about 10 and 70%by weight of total monomer present, and said hydrophobic copolymerforming between 8 and by weight of the total weight of dryultraviolet-absorbing filter layer.

2. An ultraviolet-absorbing filter layer composition according to claim1, characterized in that gelatin is used as the hydrophilic colloidbinder material.

3. An ultraviolet-absorbing filter layer composition according to claim1, characterized in that 2(2-hydroxy-4'-methacryloylamino-phenyl)-2H-benzotriazole is used as theultraviolet-absorbing, solid, water-insoluble monomer.

4. An ultraviolet-absorbing filter layer composition according to claim1, characterized in that2(2'-hydroxyphenyl)-5-methacryloylamino-2H-benzotriazole is used as theultraviolet-absorbing, solid, water-insoluble monomer.

5. An ultraviolet-absorbing filter layer composition according to claim1, characterized in. that 2(2'-hydroxy-4'-methacryoyloxyphenyl)-2H-benzotriazo1e is used as theultraviolet-absorbing, solid, water-insoluble monomer.

6. An ultraviolet-absorbing filter comprising a support and anultraviolet-absorbing filter layer composition according to claim 1.

References Cited UNITED STATES PATENTS 3,218,332 11/1965 Heller et a1252300 3,072,585 1/1963 Milionis et al 96-84 R 3,159,646 12/1964Milionis et al 252-300 3,330,656 7/1967 Schuler 96-84 R RONALD H. SMITH,Primary Examiner US. Cl. X.R. 96-84 R; 252300

